1. Field of the Invention
The present invention relates generally to a new automated laser cutting/welding system configured to produce, for example, an improved welded or cut work piece, such as an automotive body panel, side rail or structure, and a system and method for the manufacture thereof that includes an improved laser cutter/welder.
2. Background of the Invention
In the past, work pieces such as body panels or side rails for use in the automotive vehicle industry were made by stamping or drawing the panel from either a single blank of a ductile sheet metal material, including steel, or from a plurality of such blanks that were previously welded together.
The automotive vehicle industry is very competitive with respect to, among other things, quality, raw material costs, and manufacturing times required to completely fabricate and assemble a vehicle. To remain competitive, manufacturers have continuously expended enormous resources to contain, if not reduce, material costs by reducing part weight, part count, and manufacturing time while maintaining the needed high degree of quality. A considerable amount of such resources have been directed to improving and automating routine tasks such as the fastening together of various work pieces and vehicle parts such as, for example, body panels for fenders, quarter panels, trunk lids, engine compartment hoods, vehicle doors, and other various components.
Previously, multi-part sheet metal blanks have been welded together into a single work piece before being stamped into a final shape. These blanks were prepared by a variety of fastening techniques including chemical, arc, and CO2/Nd:Yag laser welding, riveting, bolting, cold forming, and similar methods. Of particular interest in recent years is the use of more efficient laser welding using CO2/Nd:Yag lasers in automated, numerically controlled manufacturing processes. Such laser welding can be accomplished for joining together sheet metal blanks at a common seam by means of, for example, a lap weld, or a butt weld. Butt welds are often preferred because only a single seam needs to be welded in contrast to lap joint which usually require that two seams be welded.
Laser cutting machines of the type to which the present invention is directed are well known in the art. In their most usual form, they comprise an elongated main frame having upstanding front or operator-side and rear or beam-side portions in substantially parallel spaced relationship with a cutting zone and a loading/unloading zone located therebetween. The parallel, upstanding, main frame portions are generally described as extending in the directions of the X-axis, while the Y-axis extends transversely of these main frame portions and the Z-axis is vertically oriented. The machine is provided with a gantry, the ends of which are mounted on the upstanding frame members for movement therealong in the X-axis directions. The gantry carries a carriage-mounted laser cutting head capable of traversing along the gantry in the Y-axis direction. Movement of the gantry in the X-axis directions and movement of the laser head carriage in the Y-axis directions assure that the laser cutting head can be located anywhere in the cutting zone of the machine.
CO2/Yag laser cutting cells available today primarily comprises one cutting head; although, some system utilize two cutting heads mounted to a single structure. When two heads are mounted on a single structure, vibrational problems arise because the starting and stopping moments from one cutting head create vibrations in the other cutting head. This vibration creates swiggles or irregularities in the cuts created by the vibrating cutting head.
This invention provides multiple cutting heads in a single cutting cell whereby vibrations created in one cutting head is isolated from the other cutting head(s).
The invention is a laser cutting cell having more than one cutting head in the cell, whereby each cutting head is supported by separate support structures to prevent the transfer of vibration from one cutting head to another. The multi-head laser cell includes a series of support structures that are staggered/stacked with respect to each other so that the lasers are isolated from each other. The x-direction rails and laser guides are mounted in staggered heights.
In the preferred embodiment, each laser cutting head has a pre-programmed dynamic operating zone to prevent collisions with other cutting heads. Furthermore, the laser cutting heads preferably have multi-axes motion control; e.g., five axis motion control.